Refining lead



Persuad ng. 50,1927. -UNITED STATES PATENT OFFICE.

2mm wl navrs, or cinnamon, massacnosnrrs.

murmme 1.1m).-

Io Drawing. i

The present invention relates to an imrovement in refining lead.

- The object of the invention is to produce a-very pure leadjfrom lead alloys by a two- 5 step process. In the first step the greater art of the alloy metals are removed, and

A specific embodiment of the present invention will be described. The product oi smelting scrap storage battery plates carries from 3% to 5% of antimony. This lead antimony alloy is treated by melting it and pouring it into a cast iron vessel, and then introducing into the vessel a suitable quantity of pulverulent litharge; The temperature of the lead will be between approximately 600 C. and approximately 883 C. These temperatures are respectively the melting points of litharge carrying antimony and of pure litharge. The lead alloy and litharge will then be stirred by any suitable means, and the litharge and lead will be brought) into intimate contact with eaqh other in bodies of small masses, and the litharge Will take up from the lead a large quantity of the antimony pres nt. Thus, the

lead by this low temperature method may from 3,62% anti-- be reduced, for example, mony to .05% antimony at a temperature of 680 C. i

This preliminarily refined lead still has an antimony content beyond that which is desired for some uses to which the metal lead or substantially all of the remaining antimony, it is then subjected to a second step, which consists in mixing molten litharge with the molten lead containing this small percentage of antimony in a suitable furnace, and maintaining the temperature above the melting point of litharge.

antimony,

While in the first step of the process it that the litharge should was not necessari 1n the secbe entirely free rom antimony 0nd step it is preferred touse lit arge which is substantially free from antimony, although good results maybe obtained y the use of litharge containing a small amount of antimony, as it will retain such antimony and take up'more antimony from he lead Application filed January 11,-

' litharge 'withthe molten above the melting point, 883

is put, and in order to remove the remaining 1926. Serial No. 50,672.

The intimate mixture of the molten lead containing. the small residual amount of antimony in bodies of small dimensions and at temperatures 0., of litharge, is a rapid operation, which results in reducing the amount of antimony present in the lead alloy to an extremely small amount. Thus, a degree of purit of lead has repeatedly been securedwhich contained only .()O3% antimony, It has also been carried to such a degree of purity as to show only, a trace of antimony.

, It will be noted alloy.

that the present invention contemplates a two-step method of removing antimony from lead, of which the first step is carried on at a low temperature, that is to say, a temperature below the melting point o-f pure litharge, and the second step is carried on at a high temperature, that IS to say,

at a temperature somewhat above the melt ing point of pure litharge. The first step removes a very large percentage of the antimony present, and the second step removes substantiallyall o'f'the remaining antimony. The first step may becarried on at low temperatures and with and in large batches. be carried on at higher temperatures in a more expensive plant, but in smaller batches, because of the greater rapidity of the reaction.

While the present invention has been described'in'connection with a specific illustration of refining lead for the purpose of removing antimony, and while this is believed to be an important use of the process because of the large quantities of antimonial lead which are available from lead storage battery plates, and because of its availability in the refining of other leads containing antimony, still it is to be understood that the invention is not limited to this particular application, as the process may be employed for the removal of other metals from lead by oxidation by the use of litharge.

Having thus described the invention, what is claimed is:

1. The method of refining lead which consists in first exposing condition to the action of pulverulent litharge by causing the two materials to be exposed to each other in bodies. of small dimensions and at temperatures between the melting point of litharge carrying the alloy metal and the melting point of pure litharge,

an inexpensive plant The second step will and second, subjecting the lead alloy product of the first step in molten condition to the action of molten litharge by causing the two materials to be exposed to each other in bodies of small dimensions at temperatures above the melting point of pure litharge.

'2. The method of refining lead which consists in first mixing lead alloy in molten contures above the melting point of pure litharge.

3. The methodof refining-"lead antimony alloys which consists in first exposing the j alloy in molten condition to the action of pulverulent litharge at temperatv res be-' tween the melting point of litharge carrying antimony (approximately 600 C.) and the melting point ofgmrelitharge (approximately 883 0.), an second, in,mix1ng the molten alloy product of the first step with molten litharge at temperatures above the melting point of pure litharge (approximately 883 C.)

In witness whereof I have signed my name to this specification.

PHILIP w. AVIS; 

